Calorie confusion

I tend not to pay too much attention to Harvard Health. It's surprising given the source, but there's a lot of pretty bad information there when it comes to diet and weight loss.

Stepping away from the skepticism of their numbers being too high, it's also a bad idea to use weight (and activity) as the sole determiner of calorie intake. Calorie goal can vary significantly based on factors such as height, age, and gender.

For example, using MFP's calculations, a 22 year old male who is 6'1" and 200 pounds would maintain on 2440. A 50 year old female who is 5'2" at the same exact weight would maintain at 1850. That's a substantial difference. So I would never decide based on weight alone.

The good news is that this isn't really something we need to Google. Put your stats in either MFP or a TDEE calculator, and they will give you your maintenance target (with MFP you would eat back your exercise calories, with TDEE you would not). That is a much better place to start from rather than worrying about how many calories per pound. Then from there, you can adjust based on your personal experience, as everyone is different. But the calculators will give you a much better starting place than that article will.

At best, it's a rough, rough rule of thumb, to get a estimate. (And I think those are higher than other estimates, too, even other TDEE estimates, especially if you're female. Was the writer male, and young? ).

The so-called "calculators" give you an estimate based on extensive research, and they consider more variables. (Keep in mind that MFP's estimate does not include intentional exercise in base calories, but expects you to add exercise when you do it. TDEE calculators include the exercies in the base calorie estimate.)

Fitness trackers (decent quality ones) give you a personalized estimate based on essentially the same research as the "calculators" do.

This is all assuming you set the inputs accurately, too, of course.

Your own logging, if you're as meticulous and consistent about it as practical, will produce the best estimate.

Still, all of them are estimates. Above, I put them in what I think is the most probable order for least to most accurate, for most people. But they're all estimates. Except for your own logging, they're giving you, in essence, the mean value (average) of a population that varies. Most people will be close (there's a small standard deviation, in statistical terms), but a few will be somewhat off (higher or lower); and a very, very few people will be off by a good bit.

It's all estimates.

I'm 5'5", female, around 135 pounds, age 64.

MFP thinks I'd maintain on around 1500 + exercise; exercise is around 250-350, usually 6 days a week.
TDEE calculators suggest about the same, for sedentary; or around 1900 for moderately active, 2100 for very active. (I'm somewhere in the moderate to very active range per Sailrabbit definitions).
My Garmin Vivoactive 3 thinks I burn 1600-1900 or so calories most of the time.

Nearly 5 years of logging data (food, exercise, scale weight) suggests I maintain on something in the low to mid 2000s, 2200-2400, maybe, but it's seasonal. Some women my age/size maintain below 1500, perhaps even less, varying of course with activity level.

OP, track your intake and exercise, and watch your weight changes. At the start, use at least 4-6 weeks of data, and if you're a premenopausal female, compare the same point in 2 or more different menstrual cycles. That will give you the best handle on your personal calorie needs.

Think of calorie goals as an estimate. Then use what your weight does; is it staying the same, going up or going down as expected, as an indicator of whether you need to be more accurate with your calorie logging or if you can add or reduce calories based on your goals. Calories burned during exercise, is also an estimate, which is why many people advise only eating back a portion instead of all of your burned calories.

Even though I'm not very active I found once I set my activity level to active, MFP gave me calories that matched up exactly with my settings. It took a while to figure out weekly vs monthly fluctuations in my weight, but now I can just dial my calorie goals in manually for the results I want.

All estimating methods are estimates, as others have already stated. I think you contribute to your own confusion by checking lots of different ones. Pick one, MFP, a TDEE calculator, whatever you wish. Use it. Track for results compared to estimates for 10 weeks. Adjust based on your own actual data.